TP-Link TL-MR3020 restore from OpenWRT to Original Firmware

If you had flashing the TP-Link MR3020 firmware to OpenWRT and now you want to restore it to the original state, here is a guide on how to make it. With this guide you will able to changing between original firmware to different version OpenWRT firmware.

I downloaded the latest firmware, I copied it to the /tmp and typed the command, after I got an error message saying, ... failed ... block
and after, I am unable to connect to the wifi, ...
any ideas ?
flushing the firmware, with usb ?
in any case, I think the WI-FI router is dead :(
Just to learn from this situation :)